Tom has a bet with Diana that she can't be nice to people for a week. Such untypical actions only lead to confusion. Baines wants to organise a glamorous grandmother contest for the old ladies in the home, the prize being a cruise for two. Since Basil wants to marry Betty, Tom approaches his son Geoffrey, whose firm is sponsoring the contest, to let Betty win, but when Betty gets cold feet and refuses to enter, Diana, having made sure a journalist friend is present to expose any 'fixing' of the contest, replaces her last minute.